The invention relates to the recycling of flux residues from soldering processes using solders composed of metal fluoroaluminates and fluorozincates.
As used herein, the term "soldering" includes both soft soldering and hard soldering (i.e., brazing).
In soldering, in particular of aluminium and aluminium alloys, fluxes composed of metal fluorometallates, e.g. composed of alkali metal fluorozincates and particularly of alkali metal fluoroaluminates, are used. Fluoroaluminates which contain potassium and/or cesium are particularly well suited. A considerable amount of the flux used for soldering is not consumed, but remains in the pipes, lines or apparatus. A further portion of the residues results from any cleaning of the soldered objects which may be carried out, from spent flux suspensions and from the regularly-performed cleaning of storage tanks. In the past these flux residues have not been re-used.